2015 Thor 31W:
Trying to be as concise as possible:
1. House batteries were very low (realize they may be permanently damaged, but removed them and checked good.)
2. With shore power (switch to "use"), voltage at terminals was 13.6
3. Started coach, and voltage increased approx. .6V. Turned off coach, and voltage returned to previous reading.
4. Removed shore power and turned on inverter. Yellow light (battery) was illuminated, and voltage on display read 13.5V.
5. Voltage rapidly dropped (5 minutes?), and gen-set kicked in (auto-gen).
*** batteries were removed, and checked good***
*** voltage at battery terminals remained a bit above 13 7 hrs after removal***
Question.. does it seem a battery issue, or something more perplexing?
Thanks ahead of time